Wide track for powered sleds



Jall- 1965 A. E. HETTEEN ETAL 3,

WIDE TRACK FOR POWERED SLEDS Filed Feb. 14, 1963 4 Sheets-Sheet 1 FIG.1

I/VI/ENTORJ ALLANEfiETTEEN ORLEN DJH/vso/v 0/1 via E. J'oH/w'a/v Jan. 5, 1965 A. E. HETTEEN ETAL 3,164,416

WIDE TRACK FOR POWERED SLEDS Filed Feb. 14, 1963 4 Sheets-Sheet 2 INVENTORS ALLAN E. HETTEEN ORLEN D. Jon/wow DA v10 E. JOHNJON VERNo/VL .J'omvsolv ALB/N R. ERIC/(JON Arrakusrr Jan. 5, 1965 TRACK FOR POWERED SLEDS WIDE 4 Sheets-Sheet 3 Filed Feb. 14, 1963 54 IIVVE/VTORJ' rILLA/YE. HETTEEN ORL EN 0. JOHNSON DA v10 5. Jo NSON l ERNONL. o/mso/v AL IN R. ER/cKso/v m$w ArroRNE Y5) 5, 1965 A. E. HETTEEN ETAL 3,164,415

WIDE TRACK FOR POWERED SLEDS Filed Feb. 14, 1965 4 Sheets-Sheet 4 INVENTORS [L flLm/v E. HETTEEN ORLEN D. Jbmvsorv DA v/o E. JbH/vso/v VERNON L .JbHNso/v AL BIN R. ER/cKso/v A'rroR/vs Ks- United States Patent 3,164,416 WIDE TRAQK FGRIGWERED SLEDS Allan E. Hetteen, David E. Johnson, Vernon L. Johnson, Albin R. Erickson, and Grlcn D. .loimson, lioseau, Minn, assignors to Polaris Industries, Inc., Ros-earl, Minn, a corporation of Minnesota Filed Feb. 14, 1963, Ser. No. 258,495 Glaims. (Cl. 395-16) This invention is a wide track for powered sleds which is novel in that it 18 made up of two narrow tracks, the

cleats of which interlace with one another at the portion near the center of the track taken as a whole which provides unusual flexibility for the unit. Additional novelty results from this structure in that it may be of relatively light construction which permits a desirable weight per square foot of area engaged by the track ratio. The track is also novel in presenting twice as many cleat ends facing either side of the track to resist lateral slipping.

It was thought that the tracks for powered sleds were limited in potential width by reason of the necessity to maintain a ratio between the square feet of space occupied by the track unit and the weight of the entire power structure of /4 lb. to the square inch when a portion of the unit is supported entirely by the powered endless track mechanism. l-ieretofore, an endless track of the type comprising cleat members extending laterally across the unit and connected to driving chains which in turn were reeved around driving and idler sprockets were i so strong and heavy that the weight per square inch of area ratio was not maintained. When the weight per square inch of area occupied by the power unit exceeds lb. per square inch, the machine becomes sluggish and will sink down through snow to an extent that renders the machine impractical. On the other hand, cleats or traction units that are as much as 30 inches in length and of such construction that they do not exceed the emperically determined lb. per square inch limit, will distort or even break when used on uneven ground or when engaged in particularly heavy work.

ccordingly, it is the principal object of this invention to provide a novel track for powered sleds.

It is a further object of this invention to provide a track that can be very strong although composed of comparatively light weight structural members.

It is a further object of this invention to provide a track for powered sleds that resists downhill sideways sliding when moving along a hillside.

A still further object of this invention is to provide a wide track sled power unit that makes it possible to provide a power unit staying within a weight to square inch of area covered by the traction unit ratio of lb. per square inch.

It is yet another object of this invention to provide a traction unit in which the traction elements adapt themselves readily to a wide range of surface conditions.

A further object of this invention is to provide an endless track for powered sleds that may employ lighter Weight driving members.

A still further object of this invention is to provide an endless track for a powered sled that is laterally flexible.

Other and further objects of the invention are those inherent and apparent in the apparatus as described, pictured and claimed.

To the accomplishment ofthe foregoing and related ice ends, this invention then comprises the features hereinand in the direction of the arrows 2-2 of FIGURE 1;

FIGURE 3 is a fragmentary side elevation of the endless track of this invention with broken lines illustrating hidden parts;

FIGURE 4 is a fragmentary plan view taken on the line and in the direction of the arrows 4-4 of FIGURE 3 with broken lines illustrating hidden parts and drawn to a larger scale than FIGURES 1, 2 and 3; 7

FIGURE 5 is a fragmentary section drawn to the same scale as and taken on the line and in the direction of the arrows 55 of FIGURE 4 with broken lines illustrating hidden parts;

FIGURE 6 is a reduced, lateral vertical section of the driving track shown on uneven ground to illustrate its flexibi ity of operation; broken lines illustrate hidden parts;

FIGURE 7 is a View comparable to FIGURE 1 of a three wide track structure with portions of the center track broken away to conserve space; broken lines illustrate hidden parts;

FIGURE 8 is a view similar to FIGURE 6 except illustrating the structure shown in FIGURE 7; and

FIGURE 9 is a view similar to FIGURE 1 of a modified form of the two track structure with broken lines illustrating hidden parts.

Referring to the drawings and specifically to FIGURE 1 thereof, there may be seen represented support ways it ill and i2 which'occupy positions at the outside and center of the entire track structure. These support ways are of any suitable material, wood being the most practical one known at this time. These elements are secured to the power unit frame, the structure of which is not material to this invention, and serve to support the ends of the cleats of the tracks.

The cleats, generally designated 14, are all alike and, therefore, not given individual numbers or described separately. Each unit consists of a channel member 15 that is flared slightly at its open end, and closed at the ends as shown at 16. Each channel member is provided at each end with a slide guide 17 which will be described in more detail in connection with FIGURES 4 and 5. Cleats 14 are secured to suitable'flexible. endless drive means such as chains 17 and 13 which are regular link chains of the type that may be reeved around and driven by sprockets. It will be seen that each of the traction members 15 is long enough to extend from a point slightly beyond an outside runner Ill and 12 and across to the opposite side of the center runner or support member 11. In this manner, the traction members overlap each other at the center but are separate and staggered as shown clearly in FIGURE 1 so that the ends of the cleats in one group extend between the ends or" the other group and vice versa.

There are at least some circumstances in which it is desirable to have a rubber tread or insert as at 19 secured within the channel member 15. These units may be held within the channel in any suitable manner as by the nut and bolt assemblies Ell.

In FIGURE 2 the view is taken through the middle supports it) and 11 and looking toward the opposite side. The manner in which the slide guides 23 engage the wooden support ways 11 is shown clearly in this view.

In FIGURE 3 may be seen the representation of. a drive shaft at 21 to which is secured a-sprocket 22 that provides a means for associating shaft 21 with a source of power as by the chain 24. Secured to this same shaft are a series, of large sprockets such as the one fragmentarily illustrated at 25 and which are arranged in spaced relation across the shaft so that the chains 17 and 18 each engage one. Corresponding idler sprockets are provided at the other end of the track.

Since the spans between the sprockets 25 are relatively short, a shaft of comparatively small diameter is adequate to provide the traction force. By way of comparison, when only two chains were used on widely spaced track members long enough to reach across a 30 inch driving unit, a shaft of the same size was found to twist under heavy stress loads encountered under some driving conditions which resulted in one end of the track becoming misaligned with respect to the other. In FIGURE 3, also, the ways, here 12, may be seen to have an upwardly curving end 26 that reacts with the track slide guides 23 to provide for a smooth engagement and separation of the cleats with the slide.

As shown in FIGURE 4, guides 23 are formed so as to have the vertical portion 27 flare slightly at each side so that regardless of which end of a traction unit the guide ends up on, it will present a flaring mouth-like arrangement in its vertical portion 27 to the end of the slide member, in FIGURE 4 the one designated 12.

In FIGURE 5, the guide member 23 may also be seen to have its horizontal portion, which is the principal sliding contact between the cleats and the ways, formed with curved front and rear portions 28 and 29. Again, regardless of the orientation of the unit with respect to the tracks, it will always present such a curving side to the curved portion 26 to the ways, here 12 for example, and

comparable portions of the other slides as the cleats come from or leave the ways so that there is no likelihood of a cleat member getting caught on the curved way ends 26 when the transition is made from the supported to a supporting position shown in FIGURE 3.

Special chain links such as the one shown at 30 in FIGURE 4 are provided with attaching plates 31 which are suitably secured to the channels as by the rivets illustratively shown at 32. The slide guides are similarly secured as by the rivets shown in broken lines at 34 in FIGURE 4.

In FIGURE 5, the rubber insert 19 may be seen to have a relieved portion as at 35 to provide space for the ends of rivets 32 and the like as well as reducing the weight of the rubber unit. This tread member is also provided with an opening laterally through it as at 36 which provides more resilience for the rubber tread and also aids in weight reduction.

Turning now to FIGURE 6, the flexibility of this divided wide track may be observed in that the track is shown carrying the vehicle body represented with broken lines at 37 over an uneven ground surface 38. The principal weight supplied as shown by the arrow 39 and as a result the vehicle remains oriented with the right hand portion of ground surface 33 rather than the left. The left hand track, however, may drop down as is clearly shown therein to maintain contact with the ground even though there is a clearance as seen at 41) between the slide guide 23 and the support way 12. Similarly this unit can adapt itself to a concave ground surface on which perhaps the ends of both track member systems would be .down slightly from the center support 11 and the weight of the vehicle would be resting on the two slide- .ways 10 and 12 primarily.

Not only has it been found possible to maintain the desired weight to square foot of space occupied by the traction unit ratio of A lb. to the square inch, but this device was also found to be highly desirable in that it offered excellent resistance to downhill sliding sideways when travelling along a side of a hill in a direction normal to the grade. Resistance to sliding laterally is determined by the number of cleat ends which in this structure is twice as great as in conventional tracks for powdered sleds. While this double track was devised primarily for the purpose of providing track support entirely across the vehicle without having any one cleat exceed 20 inches in length, therefore, this secondary advantage was derived accidentally and it makes a sled so equipped much more sure footed. In this construction, then, a track of at least 30 inches or more in Width can be supplied in which the cleats need not be stronger than ones of 20 inches in length or less.

Referring now to FIGURE 7, the structure seen there is very similar to that shown in FIGURE 1 except that there are four Wooden slides Stl, Si, 52 and 54. Three track structures 55, 56 and 57 extend between the slides and have their outer ends supported thereby. The cleat ends of track 56 extend in between the treads of tracks 51 and 52 in the same manner that the two tracks in FIG- URE l interlock with each other. Cleats, such as the one 58, are identical to those described in relation to the structure shown in FIGURE 1. Similarly also, a rubber insert, such as 59 may be provided and removably secured within the cleats as described in relation to FIGURE 1.

The principal advantage of increasing the number of tracks once the weight per square inch of track ratio has been satisfied is to provide greater flexibility. This is illustrated in FIGURE 8 where the unit, shown in lateral section on uneven ground, has a better distribution of the weight of the vehicle over the entire width of the track than is true in FIGURE 6 Where most of the Weight of the weight of the vehicle must be born by the righthand track as shown in that figure.

In FIGURE 9 is seen a modification of the structure shown in FIGURE 1 in which the cleat structures 60 and 61 are substantially identical as those shown in FIG- URE l, the principal difference in this case being that there are only three chains as at 62, 64 and 65 which are used to drive the two tracks. This is accomplished by the use of four slideways 66, 67, 68 and 6 which are so positioned that the inside ends of both of the track cleats 6% and 61 are secured to chain 64, a slideway is positioned under the inside end of the track on each side of the chain 64. The structure of course uses more slideway material but only three-quarters as much chain. It also tends to compress the track into a slightly smaller area than is true of the structure shown in FIGURE 1. It could be an advantage if a slightly narrower track but with almost the same supporting ability were desired. This track structure is also perhaps slightly less flexible than that illustrated in FIGURE 1 but nevertheless retaining sutficient flexibility to prevent the tracks from being damaged or twisted in going over at least a mildly uneven surface. Furthermore, the track treads actually get greater support than they do in the structure shown in FlGURE 1. Support 66 is inevitably capable of supporting the cleats 6G in the event that they are depressed to any extent and conversely, support 68 may serve as an intermediate support for cleats 61 if they yield to speak of. For this reason, it appears conceivable that the structure of FIGURE 9 might prove to be an even more rugged structure than that shown in FIGURE 1, although testing to date has not demonstrated to what extent this might be true. A three chain, four slide structure would be more practical in the event of chains becoming diflicult to get or in areas where chains are relatively expensive and the wood slide structure is relatively inexpensive or vice versa.

Although it is not specifically illustrated, it is clear that any artisan could adapt the structure shown in FIG- URE 7 to the type of structure illustrated in FIGURE 9 wherein there are provided two slideways for each set of tracks and adjacent track cleats would use a single chain between them. Such a structure would compare with the structure shown in FIGURE 7 substantially in the same manner that the structure shown in FIGURE 9 compares with the structure shown in FIGURE 1.

It is apparent that many modifications and variations of this invention as hereinbefore set forth may be made without departing from the spirit and scope thereof. The specific embodiments described are given by way of example only and the invention is limited by the terms of the appended claims.

What is claimed:

1. An endless track type drive, a first track unit comprising a first set of spaced apart elongated flexible endless driving members, cleats spaced along and secured to said spaced apart endless driving members, the spacing between cleats being wider than the cleats, a second identical track unit including a second set of spaced apart elongated flexible endless driving members arranged beside said first track unit and with the cleats on one of said track units positioned opposite the spaces between cleats on the other track unit, and means associated with both sets of spaced apart elongated endless driving members to maintain the cleats of one set misaligned with reference to the cleats of the other set, and supporting slideways engaging and supporting each of said track units.

2. The structure of claim 1 in which said cleats comprise flared channel members having closed ends.

3. The structure of claim 2 in which said channel memhers are provided with longitudinally hollow rubber tread inserts that extend below the lower ends of said channels.

4. The structure of claim 1 in which said cleats are provided with slide guides having both vertical and horizontal portions each being flared with respect to longitudinal movement of said slide guides over said slideways.

5. The structure of claim 1 in which said first and second set of spaced apart elongated flexible endless driving means are chains, one shaft at each end of said track and said means for maintaining cleat misalignment are sprockets secured to said shaft and engaging said chains.

6. The endless track type drive of claim 1 in which one of the spaced apart elongated flexible endless driving members of each set is common to the two sets.

7. A track for an endless tread drive type powered sled comprising: first, second and third slideways extending longitudinally along the center and near the two sides of said track area, first and second sprocket carrying shafts rotatably supported at opposite ends of said track area, a first pair of chains reeved over sprockets on said first and second shafts to be movably suspended between said first and second slideways, a second pair of chains reeved over other sprockets on said first and second shafts as to be movably suspended between the second and third slideways, cleats secured between said first mentioned pair of chains and overlapping the two slideways between which said first mentioned pair of chains are rotatably supported, cleats secured to said second mentioned pair of chains and overlapping the two slideways between which are second mentioned pair of chains rotatably supported, said cleats being spaced equally along said pairs of chains, the ends of the cleats secured to one of said pairs of chains lying in the spaces between the ends of the cleats secured-to the other of said pairs of chains and being physically separated therefrom to allow movement bteween the cleats of the first pair of chains relative to the cleats of the second pair of chains, said cleats comprise flared channel members having closed ends, rubber tread inserts that extend below the lower ends of said channels secured therein, and slide guides having both vertical and horizontal portions each being flared with respect to longitudinal movement of said track; said slide guides being secured to the ends of said cleats and engaging said slideways.

8. A track for an endless tread drive type powered sled comprising: first, second and third slideways extending longitudinally along the center and near the two sides of said track area, a first pair of chains rotatably suspended between said first and second slideways, a second pair of chains rotatably supported between the second and third slideways, cleats secured between said first mentioned pair of chains and overlapping the two slideways between which said first mentioned pair of chains are rotatably supported, cleats secured to said second mentioned pair of chains and overlapping the two slideways between which said second mentioned pair of chains are rotatably supported, said cleats being spaced equally along said pairs of chains, the ends of the cleats secured to one of said pairs of chains lying in the spaces between the ends of the cleats secured to the other of said pairs of chains and being physically separated therefrom to allow longi tudinal pivotal movement between the cleats of the first pair of chains and the cleats of the second pair of chains.

9. The structure of claim 8 in which said cleats comprise closed end channels having rubber treads therein, said rubber treads are molded with longitudinal openings therein.

10. The structure of claim 8 in which slide guides having both vertical and horizontal portions each being flared with respect to longitudinal movement of said slide guides over; said slideways being secured to the ends of said cleats and engage said slideways.

References Cited in the file of this patent UNITED STATES PATENTS 1,774,797 Knox Sept. 2, 1930 2,312,072 Broadwater Feb. 23, 1943 2,323,526 Eliason July 6, 1943 2,786,725 Thorne Mar. 26, 1957 

1. AN ENDLESS TRACK TYPE DRIVE, A FIRST TRACK UNIT COMPRISING A FIRST SET OF SPACED APART ELONGATED FLEXIBLE ENDLESS DRIVING MEMBERS, CLEATS SPACED ALONG AND SECURED TO SAID SPACED APART ENDLESS DRIVING MEMBERS, THE SPACING BETWEEN CLEATS BEING WIDER THAN THE CLEATS, A SECOND IDENTRICAL TRACK UNIT INCLUDING A SECOND SET OF SPACED APART ELONGATED FLEXIBLE ENDLESS DRIVING MEMBERS ARRANGED BESIDE AND FIRST TRACK UNIT AND WITH THE CLEATS ON ONE OF SAID TRACK UNITS POSITIONED OPPOSITE THE SPACES BETWEEN CLEATS ON THE OTHER TRACK UNIT, AND MEANS ASSOCIATED WITH BOTH SETS OF SPACED APART ELONGATED ENDLESS DRIVING MEMBERS TO MAINTAIN THE CLEATS OF ONE SET MISALIGNED WITH REFERENCE TO THE CLEATS OF THE OTHER SET, AND SUPPORTING SLIDEWAYS ENAGING AND SUPPORTING EACH OF SAID TRACK UNITS. 